The invention relates to a process of coal hydrogenation in which a flowable mixture of finely divided coal particles and liquid hydrocarbons are brought to a high pressure and reaction temperature and are hydrogenated with hydrogen in the presence of the hydrogenation catalyst, whereupon the gaseous products are separated from liquid and solid reaction products.
Conventionally, finely dispersed catalysts are used for hydrogenation. In the past, the employed catalysts were mainly materials containing iron oxide (e.g. Bayermass, Luxmass or iron ore), tin oxalate, cobalt molybdate and others (partly in combination with co-catalysts), having a concentration of up to 6% by weight calculated on dry coal usage (Fuel Processing Technology, 2 (1979) 235 to 251).
The catalysts used in the coal hydrogenation are used only once, as their separation from the liquefied product can be effected only together with the unconverted coal or its mineral portion, respectively. For this reason, after treatment of the hydrogenation product, and eventually possibly after partial oxidation of the residue, the catalysts are deposited as slag and are discarded.
A need persists for a cost-effective suitable hydrogenation catalyst which can be reused after it is used in the coal hydrogenation process, thereby realizing savings in cost over conventional hydrogenation catalysts.